U2's frontman is used to being outspoken, but it's a rare day that Bono is booed when he takes the stage.
The Irish superstars played to around 50,000 fans during their first ever show in Turkey, at Istanbul's Ataturk Olympic Stadium.
Faux pas: sometimes it's best to keep your mouth shut. Even if you're Bono.
The concert has coincided with a contraversial point in Turkey's history: on September 12 the country's people will vote on a constitutional referendum that will change the constitution made exactly 30 years ago. The changes will mean civilian courts will be more powerful than their military counterparts, and women and children will have more rights. However, opponents claim the referendum will give the government more control over the courts.
So when Bono spoke after the band's first number (Beautiful Day) about walking from west to east across the Bosphorus with State Minister and EU chief negotiator Egemen Bagis, a strong supporter of the referendum, the crowd reacted with boos and jeers. Ever the charmer, Bono backpedalled with quick assurances that he wouldn't talk politics, and instead began to wax lyrical about Turkey's global importance. Wise move, Bono.
Istanbul is this year's European Capital of Culture, and many see the U2 gig as a jewel in the crown of the city's events.
See a few of the pictures here.